Selective ammoxidation catalysts

ABSTRACT

A catalytic composition useful for the conversion of an olefin selected from the group consisting of propylene, isobutylene or mixtures thereof, to acrylonitrile, methacrylonitrile, and mixtures thereof. The catalytic composition comprises a complex of metal oxides comprising bismuth, molybdenum, iron, cerium and other promoters, wherein the ratio of bismuth to cerium ratio in the composition is greater than or equal to 0.45 and less than or equal to 1.5.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an improved catalyst for use in theammoxidation of an unsaturated hydrocarbon to the correspondingunsaturated nitrile. In particular, the present invention is directed toan improved catalytic composition for the ammoxidation of propyleneand/or isobutylene to acrylonitrile and/or methacrylonitrile,respectively, wherein said catalyst comprises a complex of metal oxidescomprising bismuth, molybdenum, iron, cerium and other promoters andwherein said catalyst is characterized by ratio of bismuth to ceriumcontained in the catalyst.

2. Description of the Prior Art

Catalysts containing oxides of iron, bismuth and molybdenum, promotedwith suitable elements, have long been used for the conversion ofpropylene and/or isobutylene at elevated temperatures in the presence ofammonia and oxygen (usually in the form of air) to manufactureacrylonitrile and/or methacrylonitrile. In particular, Great BritainPatent 1436475; U.S. Pat. Nos. 4,766,232; 4,377,534; 4,040,978;4,168,246; 5,223,469 and 4,863,891 are each directed tobismuth-molybdenum-iron catalysts which may be promoted with the GroupII elements to produce acrylonitrile. In addition, U.S. Pat. Nos.5,093,299, 5,212,137, 5,658,842, 5,834,394, 8,153,546 and CN103418400are directed to bismuth-molybdenum promoted catalysts exhibiting highyields to acrylonitrile.

In part, the instant invention relates to a bismuth-molybdenum-ironcatalysts promoted with cerium. It has been discovered that bycontrolling the relative ratio of bismuth to cerium impacts theperformance of the catalyst.

SUMMARY OF THE INVENTION

The present invention is directed to an improved mixed metal oxidecatalyst for the ammoxidation of propylene and/or isobutylene. Thisimproved catalyst provides greater overall conversion of the propyleneand/or isobutylene to nitriles (i.e. compounds having the function group“—CN”, such as acrylonitrile, methacrylonitrile, acetonitrile andhydrogen cyanide), higher hydrogen cyanide production, and greaterammonia utilization efficiency.

In one embodiment, the invention is directed to a catalytic compositioncomprising a complex of metal oxides wherein the relative ratios of thelisted elements in said catalyst are represented by the followingformula:

Mo_(m)Bi_(a)Fe_(b)A_(c)D_(d)E_(e)F_(f)G_(g)Ce_(h)O_(x)

-   wherein A is at least one element selected from the group consisting    of sodium, potassium, rubidium and cesium; and    -   D is at least one element selected from the group consisting of        nickel, cobalt, manganese, zinc, magnesium, calcium, strontium,        cadmium and barium;    -   E is at least one element selected from the group consisting of        chromium, tungsten, boron, aluminum, gallium, indium,        phosphorus, arsenic, antimony, vanadium and tellurium;    -   F is at least one element selected from the group consisting of        lanthanum, praseodymium, neodymium, samarium, europium,        gadolinium, terbium, dysprosium, holmium, erbium thulium,        ytterbium, lutetium, scandium, yttrium, titanium, zirconium,        hafnium, niobium, tantalum, aluminum, gallium, indium, thallium,        silicon and germanium;    -   G is at least one element selected from the group consisting of        silver, gold, ruthenium, rhodium, palladium, osmium, iridium,        platinum and mercury; and        a, b, c, d, e, f, g, h and x are, respectively, the atomic        ratios of bismuth (Bi), iron (Fe), A, D, E, F, G, cerium (Ce)        and oxygen (O), relative to “m” atoms of molybdenum (Mo),        wherein    -   a is from 0.05 to 7,    -   b is from 0.1 to 7,    -   c is from 0.01 to 5,    -   d is from 0.1 to 12,    -   e is from 0 to 5,    -   f is from 0 to 5,    -   g is from 0 to 0.2,    -   h is from 0.01 to 5,    -   m is from 10 to 15, and    -   x is the number of oxygen atoms required to satisfy the valence        requirements of the other component elements present;        wherein 0.45≦a/h<1.5, and 0.3≦(a+h)/d.

The present invention is also directed to processes for the conversionof an olefin selected from the group consisting of propylene andisobutylene or mixtures thereof, to acrylonitrile, and/ormethacrylonitrile, and other by-product nitriles (i.e. compounds havingthe function group “—CN”, such acetonitrile and hydrogen cyanide) andmixtures thereof, by reacting in the vapor phase at an elevatedtemperature and pressure said olefin with a molecular oxygen containinggas and ammonia in the presence of the mixed metal oxide catalystdescribed above.

DETAILED DESCRIPTION OF THE INVENTION

The present invention is directed to an improved mixed metal oxidecatalyst for the ammoxidation of propylene and/or isobutylene. Thisimproved catalyst provides greater overall conversion of the propyleneand/or isobutylene to nitriles (i.e. compounds having the function group“—CN”, such as acrylonitrile, methacrylonitrile, acetonitrile andhydrogen cyanide), higher hydrogen cyanide production, and greaterammonia utilization efficiency.

The Catalyst:

The present invention is directed to a multi-component mixed metal oxideammoxidation catalytic composition comprising a complex of catalyticoxides wherein the elements and the relative ratios of the elements insaid catalytic composition are represented by the following formula:

A catalytic composition comprising a complex of metal oxides wherein therelative ratios of the listed elements in said catalyst are representedby the following formula:

Mo_(m)Bi_(a)Fe_(b)A_(c)D_(d)E_(e)F_(f)G_(g)Ce_(h)O_(x)

-   wherein A is at least one element selected from the group consisting    of sodium, potassium, rubidium and cesium; and    -   D is at least one element selected from the group consisting of        nickel, cobalt, manganese, zinc, magnesium, calcium, strontium,        cadmium and barium;    -   E is at least one element selected from the group consisting of        chromium, tungsten, boron, aluminum, gallium, indium,        phosphorus, arsenic, antimony, vanadium and tellurium;    -   F is at least one element selected from the group consisting of        lanthanum, praseodymium, neodymium, samarium, europium,        gadolinium, terbium, dysprosium, holmium, erbium thulium,        ytterbium, lutetium, scandium, yttrium, titanium, zirconium,        hafnium, niobium, tantalum, aluminum, gallium, indium, thallium,        silicon, germanium and led than about 10 ppm lead;    -   G is at least one element selected from the group consisting of        silver, gold, ruthenium, rhodium, palladium, osmium, iridium,        platinum and mercury; and        a, b, c, d, e, f, g, h and x are, respectively, the atomic        ratios of bismuth (Bi), iron (Fe), A, D, E, F, G, cerium (Ce)        and oxygen (O), relative to “m” atoms of molybdenum (Mo),        wherein    -   a is from 0.05 to 7,    -   b is from 0.1 to 7,    -   c is from 0.01 to 5,    -   d is from 0.1 to 12,    -   e is from 0 to 5,    -   f is from 0 to 5,    -   g is from 0 to 0.2,    -   h is from 0.01 to 5,    -   m is from 10 to 15, and    -   x is the number of oxygen atoms required to satisfy the valence        requirements of the other component elements present;        wherein 0.45≦a/h<1.5, and 0.3≦(a+h)/d.        In an independent embodiment, a catalytic composition comprising        a complex of metal oxides wherein the relative ratios of the        listed elements in said catalyst are represented by the        following formula:

Mo_(m)Bi_(a)Fe_(b)A_(c)D_(d)E_(e)F_(f)G_(g)Ce_(h)O_(x)

-   wherein A is at least one element selected from the group consisting    of sodium, potassium, rubidium and cesium; and    -   D is at least one element selected from the group consisting of        nickel, cobalt, manganese, zinc, magnesium, calcium, strontium,        cadmium and barium;    -   E is at least one element selected from the group consisting of        chromium, tungsten, boron, aluminum, gallium, indium,        phosphorus, arsenic, antimony, vanadium and tellurium;    -   F is at least one element selected from the group consisting of        lanthanum, praseodymium, neodymium, samarium, europium,        gadolinium, terbium, dysprosium, holmium, erbium thulium,        ytterbium, lutetium, scandium, yttrium, titanium, zirconium,        hafnium, niobium, tantalum, aluminum, gallium, indium, thallium,        silicon, lead and germanium;    -   G is at least one element selected from the group consisting of        silver, gold, ruthenium, rhodium, palladium, osmium, iridium,        platinum and mercury; and        a, b, c, d, e, f, g, h, and x are, respectively, the atomic        ratios of bismuth (Bi), iron (Fe), A, D, E, F, G, cerium (Ce)        and oxygen (O), relative to “m” atoms of molybdenum (Mo),        wherein    -   a is from 0.05 to 7,    -   b is from 0.1 to 7,    -   c is from 0.01 to 5,    -   d is from 0.1 to 12,    -   e is from 0 to 5,    -   f is from 0 to 5,    -   g is from 0 to 0.2,    -   h is from 0.01 to 5,    -   m is from 10 to 15, and    -   x is the number of oxygen atoms required to satisfy the valence        requirements of the other component elements present;        wherein 0.45≦a/h<1.5 and 0.3≦(a+h)/d≦0.4.        In an independent embodiment, a catalytic composition comprising        a complex of metal oxides wherein the relative ratios of the        listed elements in said catalyst are represented by the        following formula:

Mo_(m)Bi_(a)Fe_(b)A_(c)D_(d)E_(e)F_(f)G_(g)Ce_(h)O_(x)

-   wherein A is at least one element selected from the group consisting    of sodium, potassium, rubidium and cesium; and    -   D is at least one element selected from the group consisting of        nickel, cobalt, manganese, zinc, magnesium, calcium, strontium,        cadmium and barium;    -   E is at least one element selected from the group consisting of        chromium, tungsten, boron, aluminum, gallium, indium,        phosphorus, arsenic, antimony, vanadium and tellurium;    -   F is at least one element selected from the group consisting of        lanthanum, praseodymium, neodymium, samarium, europium,        gadolinium, terbium, dysprosium, holmium, erbium thulium,        ytterbium, lutetium, scandium, yttrium, titanium, zirconium,        hafnium, niobium, tantalum, aluminum, gallium, indium, thallium,        silicon, lead and germanium;    -   G is at least one element selected from the group consisting of        silver, gold, ruthenium, rhodium, palladium, osmium, iridium,        platinum and mercury; and        a, b, c, d, e, f, g, h, and x are, respectively, the atomic        ratios of bismuth (Bi), iron (Fe), A, D, E, F, G, cerium (Ce)        and oxygen (O), relative to “m” atoms of molybdenum (Mo),        wherein    -   a is from 0.05 to 7,    -   b is from 0.1 to 7,    -   c is from 0.01 to 5,    -   d is from 0.1 to 12,    -   e is from 0 to 5,    -   f is from 0 to 5,    -   g is from 0 to 0.2,    -   h is from 0.01 to 5,    -   m is from 10 to 15, and    -   x is the number of oxygen atoms required to satisfy the valence        requirements of the other component elements present;        wherein 0.7≦a/h<1.5 and 0.3≦(a+h)/d.

In an independent embodiment, a catalytic composition comprising acomplex of metal oxides wherein the relative ratios of the listedelements in said catalyst are represented by the following formula:

Mo_(m)Bi_(a)Fe_(b)A_(c)D_(d)E_(e)F_(f)G_(g)Ce_(h)O_(x)

-   wherein A is at least one element selected from the group consisting    of sodium, potassium, rubidium and cesium; and    -   D is at least one element selected from the group consisting of        nickel, cobalt, manganese, zinc, magnesium, calcium, strontium,        cadmium and barium;    -   E is at least one element selected from the group consisting of        chromium, tungsten, boron, aluminum, gallium, indium,        phosphorus, arsenic, antimony, vanadium and tellurium;    -   F is at least one element selected from the group consisting of        lanthanum, praseodymium, neodymium, samarium, europium,        gadolinium, terbium, dysprosium, holmium, erbium thulium,        ytterbium, lutetium, scandium, yttrium, titanium, zirconium,        hafnium, niobium, tantalum, aluminum, gallium, indium, thallium,        silicon, germanium and less than about 10 ppm lead;    -   G is at least one element selected from the group consisting of        silver, gold, ruthenium, rhodium, palladium, osmium, iridium,        platinum and mercury; and        a, b, c, d, e, f, g, h, and x are, respectively, the atomic        ratios of bismuth (Bi), iron (Fe), A, D, E, F, G, cerium (Ce)        and oxygen (O), relative to “m” atoms of molybdenum (Mo),        wherein    -   a is from 0.05 to 7,    -   b is from 0.1 to 7,    -   c is from 0.01 to 5,    -   d is from 0.1 to 12,    -   e is from 0 to 5,    -   f is from 0 to 5,    -   g is from 0 to 0.2,    -   h is from 0.01 to 5,    -   m is from 10 to 15, and    -   x is the number of oxygen atoms required to satisfy the valence        requirements of the other component elements present;        wherein 0≦a/h<1.5 and 0.3≦(a+h)/d.

In independent embodiments, 0.45≦a/h, 0.65≦a/h, 0.7≦a/h, 0.8≦a/h, or,0.90≦a/h. In other independent embodiments, a/h≦1.2. In one embodiment,0.8≦h/b≦5. In other independent embodiments: 0.3≦(a+h)/d≦1;0.3≦(a+h)/d≦0.8; 0.3≦(a+h)/d≦0.6; or 0.3≦(a+h)/d≦0.4. In otherembodiments (each line below being an embodiment),

-   -   0.45≦a/h<1.5 and 0.3≦(a+h)/d,    -   0.65≦a/h<1.5 and 0.3≦(a+h)/d,    -   0.70≦a/h<1.5 and 0.3≦(a+h)/d,    -   0.80≦a/h<1.5 and 0.3≦(a+h)/d,    -   0.90≦a/h<1.5 and 0.3≦(a+h)/d,    -   0.45≦a/h<1.5, 0.3≦(a+h)/d and 0.8≦h/b≦5,    -   0.65≦a/h<1.5, 0.3≦(a+h)/d and 0.8≦h/b≦5,    -   0.70≦a/h<1.5, 0.3≦(a+h)/d and 0.8≦h/b≦5,    -   0.80≦a/h<1.5, 0.3≦(a+h)/d and 0.8≦h/b≦5,    -   0.90≦a/h<1.5, 0.3≦(a+h)/d and 0.8≦h/b≦5,    -   0.90≦a/h≦1.2 and 0.3≦(a+h)/d, and    -   0.45≦a/h≦1.2, 0.3≦(a+h)/d and 0.8≦h/b≦5.    -   0.65≦a/h≦1.2, 0.3≦(a+h)/d and 0.8≦h/b≦5.    -   0.70≦a/h≦1.2, 0.3≦(a+h)/d and 0.8≦h/b≦5.    -   0.80≦a/h≦1.2, 0.3≦(a+h)/d and 0.8≦h/b≦5.    -   0.90≦a/h≦1.2, 0.3≦(a+h)/d and 0.8≦h/b≦5,    -   0.45≦a/h≦1.5 and 0.3≦(a+h)/d≦1,    -   0.65≦a/h≦1.5 and 0.3≦(a+h)/d≦1,    -   0.70≦a/h≦1.5 and 0.3≦(a+h)/d≦1,    -   0.80≦a/h≦1.5 and 0.3≦(a+h)/d≦1,    -   0.90≦a/h≦1.5 and 0.3≦(a+h)/d≦1,    -   0.45≦a/h≦1.5, 0.3≦(a+h)/d≦1 and 0.8≦h/b≦5,    -   0.65≦a/h≦1.5, 0.3≦(a+h)/d≦1 and 0.8≦h/b≦5,    -   0.70≦a/h≦1.5, 0.3≦(a+h)/d≦1 and 0.8≦h/b≦5,    -   0.80≦a/h≦1.5, 0.3≦(a+h)/d≦1 and 0.8≦h/b≦5,    -   0.90≦a/h≦1.5, 0.3≦(a+h)/d≦1 and 0.8≦h/b≦5,    -   0.90≦a/h≦1.2 and 0.3≦(a+h)/d≦1, and    -   0.45≦a/h≦1.2, 0.3≦(a+h)/d≦1 and 0.8≦h/b≦5.    -   0.65≦a/h≦1.2, 0.3≦(a+h)/d≦1 and 0.8≦h/b≦5.    -   0.70≦a/h≦1.2, 0.3≦(a+h)/d≦1 and 0.8≦h/b≦5.    -   0.80≦a/h≦1.2, 0.3≦(a+h)/d≦1 and 0.8≦h/b≦5.    -   0.90≦a/h≦1.2, 0.3≦(a+h)/d≦1 and 0.8≦h/b≦5.

In one embodiment the catalyst contains no tellurium, antimony orselenium. In another embodiment, the components or elements designatedby “E” in the above formula may also include tellurium and/or antimony.In one embodiment, h is from 0.01 to 5. In one embodiment, “F” mayadditionally include lead (Pb). In one embodiment, “F” may additionallyinclude less than about 10 ppm lead (Pb). In another embodiment, “F”does not include lead (Pb). In one embodiment, “m” is 12.

In the embodiments where 0.8≦h/b≦5, “h/b” represents the ratio of ceriumto iron in the catalyst and for any catalyst formulation this ratio issimply the moles of cerium (as represented by the subscript for ceriumin the formula) divided by the moles of iron (as represented by thesubscript for iron in the formula). It has been discovered thatcatalysts described by the above formula wherein 0.8≦h/b≦5 tend to bestronger in that they have a lower attrition loss as determined by asubmerged jet attrition test.

As used herein, “catalytic composition” and “catalyst” are synonymousand used interchangeably. As used herein, a “rare earth element” meansat least one of lanthanum, cerium, praseodymium, neodymium, promethium,samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium,thulium, ytterbium, scandium and yttrium (while cerium is a rare earthelement, it is excluded from this list because cerium is a separatelylisted component of the catalyst described herein).

The catalyst of the present invention may be used either supported orunsupported (i.e. the catalyst may comprise a support). Suitablesupports are silica, alumina, zirconium, titania, or mixtures thereof. Asupport typically serves as a binder for the catalyst and results in astronger (i.e. more attrition resistant) catalyst. However, forcommercial applications, an appropriate blend of both the active phase(i.e. the complex of catalytic oxides described above) and the supportis crucial to obtain an acceptable activity and hardness (attritionresistance) for the catalyst. Typically, the support comprises between40 and 60 weight percent of the supported catalyst. In one embodiment ofthis invention, the support may comprise as little as about 30 weightpercent of the supported catalyst. In another embodiment of thisinvention, the support may comprise as much as about 70 weight percentof the supported catalyst.

In one embodiment the catalyst is supported using a silica sol.Typically, silica sols contain some sodium. In one embodiment, thesilica sol contains less than 600 ppm sodium. In another embodiment, thesilica sol contains less than 200 ppm sodium. Typically, the averagecolloidal particle diameter of the silica sol is between about 15 nm andabout 50 nm. In one embodiment of this invention, the average colloidalparticle diameter of the silica sol is about 10 nm and can be as low asabout 4 nm. In another embodiment of this invention, the averagecolloidal particle diameter of the silica sol is about 100 nm. Inanother embodiment of this invention, the average colloidal particlediameter of the silica sol is about 20 nm. In another embodiment of thisinvention, the average colloidal particle diameter of the silica sol isabout 40 nm.

Catalyst Preparation:

The catalyst may be prepared by any of the numerous methods of catalystpreparation which are known to those of skill in the art. A typicalpreparation method will begin with the formation of a mixture of water,a molybdenum source compound and a support material (e.g. silica sol).Separately, source compounds of the remaining elements in the catalystare combined in water to form a second mixture. These two mixtures arethen combined with stirring at a slightly elevated temperature(approximately 40° C.) to form a catalyst precursor slurry. The catalystprecursor slurry is then dried and denitrified and then calcined asdescribed below.

In one embodiment, the elements in the above identified catalystcomposition are combined together in an aqueous catalyst precursorslurry, the aqueous precursor slurry so obtained is dried to form acatalyst precursor, and the catalyst precursor is calcined to form thecatalyst. However, unique to the process of the instant invention is thefollowing:

(i) combining, in an aqueous solution, source compounds of Bi and Ce,and optionally one or more of Na, K, Rb, Cs, Ca, lanthanum,praseodymium, neodymium, samarium, europium, gadolinium, terbium,dysprosium, holmium, erbium, thulium, ytterbium, lutetium, scandium,yttrium, Pb, and W, to form a mixture (i.e. a first mixture),

(ii) adding a source compound of molybdenum to the mixture (i.e. thefirst mixture) to react with the mixture and form a precipitate slurry,and

(iii) combining the precipitate slurry with source compounds of theremaining elements and of the remaining molybdenum in the catalyst toform the aqueous catalyst precursor slurry.

As used herein, “source compounds” are compounds which contain and/orprovide one or more of the metals for the mixed metal oxide catalystcomposition. As used herein, “remaining elements” or “remaining elementsin the catalyst” refers to those elements and the quantity of thoseelements represented by “A”, “D”, “E”, “F” and “G” in the above formulawhich were not included in the first mixture. In one embodiment, someelements may be a part of both the first and second mixture. Further, asused herein, “remaining molybdenum” or “remaining molybdenum in thecatalyst” refers to that quantity of molybdenum required in the finishedcatalyst which was not present (i.e. not included in the preparation of)in the precipitate slurry. Lastly, the sum of the quantities ofmolybdenum provided in the source compounds of molybdenum added in (ii)and (iii) is equal to the total quantity of molybdenum present in thecatalyst.

In the above catalyst preparation, the source compounds of the remainingelements and of the remaining molybdenum which are combined with theprecipitate slurry may be combined in any order or combination of suchremaining elements and remaining molybdenum. In one embodiment, amixture of the source compounds of the remaining elements and of theremaining molybdenum is combined with the precipitate slurry to form theaqueous catalyst precursor slurry. In another embodiment, (i) a mixtureof the source compounds of the remaining elements is combined with theprecipitate slurry, and (ii) source compounds of the remainingmolybdenum are separately added to the precipitate slurry to form theaqueous catalyst precursor slurry. In another embodiment, sourcecompounds of the remaining elements and of the remaining molybdenum areadded individually (i.e. one at a time) to the precipitate slurry. Inanother embodiment, multiple (i.e. more than one) mixtures of sourcecompounds of the remaining elements and of the remaining molybdenum,wherein each mixture contains one or more of the source compounds of theremaining elements or of the remaining molybdenum, are separately added(i.e. one mixture at a time or multiple mixtures added simultaneously)to the precipitate slurry to form the aqueous catalyst precursor slurry.In yet another embodiment, a mixture of source compounds of theremaining elements is combined with a source compound of molybdenum andthe resulting mixture is then added to the precipitate slurry to formthe catalyst precursor slurry. In yet another embodiment, the support issilica (SiO₂) and the silica is combined with a source compound for theremaining molybdenum prior to combining the remaining molybdenum withthe precipitate slurry (i.e. the silica and a source compound for theremaining molybdenum are combined to form a mixture and then thismixture is added to the precipitate slurry, individually or incombination with one or more source compounds of the remainingelements).

In the above catalyst preparation, molybdenum is added both in thepreparation of the precipitate slurry and in the preparation of theaqueous catalyst precursor slurry. On an atomic level, the minimumamount of molybdenum added to form the precipitate slurry is determinedby the following relationship

-   -   Mo=1.5(Bi+Ce)+0.5(Rb+Na+K+Cs)+(Ca)+1.5 (sum of the number of        atoms of lanthanum, praseodymium, neodymium, samarium, europium,        gadolinium, terbium, dysprosium, holmium, erbium, thulium,        ytterbium, lutetium, scandium and yttrium)+(Pb)−(W)        Wherein in the above relationship “Mo” is the number of atoms of        molybdenum to be added to the first mixture, and “Bi”, “Ce”,        “Rb”, “Na”, “K”, “Cs”, “Ca”, “Pb” and “W” are the number of        atoms of bismuth, cerium, rubidium, sodium, potassium, cesium,        calcium, lead and tungsten respectively, present in the first        mixture.

In the above catalyst preparation, typically, the amount of molybdenumadded to the first mixture to form the precipitate slurry is about 20 to35% of the total molybdenum in the final catalyst. In one embodiment, asource compound for the remaining molybdenum present in the catalyst isadded to the mixture of the source compounds of the remaining elements(i.e. the second mixture) prior to the combination of the mixture of theremaining elements with the precipitate slurry to form the catalystprecursor slurry. In other embodiments, a source compound of molybdenumcontaining the remaining molybdenum present in the catalyst is added tothe precipitate slurry either prior to, after or simultaneously with,the mixture of the source compounds of the remaining elements (i.e. thesecond mixture) in order to form the catalyst precursor slurry.

In the above preparation, source compounds of Bi and Ce, and optionallyone or more of Na, K, Rb, Cs, Ca, a rare earth element, Pb and W, arecombined in an aqueous solution to form a mixture. In one embodiment,bismuth nitrate and optionally other metal nitrates (i.e. nitrates ofNa, K, Rb, Cs, Ca, a rare earth element and/or Pb) are dissolved in anaqueous solution of ceric ammonium nitrate. If tungsten is added, thesource compound is typically ammonium paratungstate, (NH₄)₁₀H₂(W₂O₇)₆.

Added to the mixture comprising the bismuth and cerium (and optionallyone or more of Na, K, Rb, Cs, Ca, a rare earth element, Pb and/or W) isa source compound of molybdenum. In one embodiment this source compoundof molybdenum is ammonium heptamolybdate dissolved in water. Upon theaddition of the molybdenum source compound to the mixture comprising thebismuth and cerium, a reaction will occur which will result in aprecipitate and the resulting mixture is the precipitate slurry.

The precipitate slurry is then combined with a mixture of sourcecompound of the remaining elements of the catalyst and a source compoundof molybdenum, to form the aqueous catalyst precursor slurry. Themixture of source compounds of the remaining elements and a sourcecompound of molybdenum may be prepared by combining source compounds ofthe remaining elements in an aqueous solution (e.g. source compounds arecombined in water) and then adding a source compound of molybdenum. Inone embodiment this source compound of molybdenum is ammoniumheptamolybdate dissolved in water. When combining the precipitate slurrywith the remaining elements/molybdenum mixture, the order of addition isnot important, i.e. the precipitate slurry may be added to the remainingelements/molybdenum mixture or the remaining elements/molybdenum mixturemay be added to the precipitate slurry. The aqueous catalyst precursorslurry is maintained at an elevated temperature.

The amount of aqueous solvent in each of the above described aqueousmixtures and slurries may vary due to the solubilities of the sourcecompounds combined to form the particular mixed metal oxide. The amountof aqueous solvent should at least be sufficient to yield a slurry ormixture of solids and liquids which is able to be stirred.

In any case, the source compounds are preferably combined and/or reactedby a protocol that comprises mixing the source compounds during thecombination and/or reaction step. The particular mixing mechanism is notcritical, and can include for example, mixing (e.g., stirring oragitating) the components during the reaction by any effective method.Such methods include, for example, agitating the contents of the vessel,for example by shaking, tumbling or oscillating the component-containingvessel. Such methods also include, for example, stirring by using astirring member located at least partially within the reaction vesseland a driving force coupled to the stifling member or to the reactionvessel to provide relative motion between the stifling member and thereaction vessel. The stifling member can be a shaft-driven and/orshaft-supported stifling member. The driving force can be directlycoupled to the stirring member or can be indirectly coupled to thestirring member (e.g., via magnetic coupling). The mixing is generallypreferably sufficient to mix the components to allow for efficientreaction between components of the reaction medium to form a morehomogeneous reaction medium (e.g., and resulting in a more homogeneousmixed metal oxide precursor) as compared to an unmixed reaction. Thisresults in more efficient consumption of starting materials and in amore uniform mixed metal oxide product. Mixing the precipitate slurryduring the reaction step also causes the precipitate to form in solutionrather than on the sides of the reaction vessel. More advantageously,having the precipitate form in solution allows for particle growth onall faces of the particle rather than the limited exposed faces when thegrowth occurs out from the reaction vessel wall.

A source compound of molybdenum may include molybdenum (VI) oxide(MoO₃), ammonium heptamolybdate or molybdic acid. The source compound ofmolybdenum may be introduced from any molybdenum oxide such as dioxide,trioxide, pentoxide or heptaoxide. However, it is preferred that ahydrolyzable or decomposable molybdenum salt be utilized as sourcecompound of molybdenum.

Typical source compounds for bismuth, cerium and the remaining elementsof the catalyst are nitrate salts of the metals. Such nitrate salts arereadily available and easily soluble.

A source compound of bismuth may include an oxide or a salt which uponcalcination will yield the oxide. The water soluble salts which areeasily dispersed but form stable oxides upon heat treating arepreferred. In one embodiment the source compound of bismuth is bismuthnitrate, Bi(NO₃)₃. 5H₂O

A source compound of cerium may include an oxide or a salt which uponcalcination will yield the oxide. The water soluble salts which areeasily dispersed but form stable oxides upon heat treating arepreferred. In one embodiment the source compound of cerium is cericammonium nitrate, (NH₄)₂Ce(NO₃)₆.

A source compound of iron may be obtained from any compound of ironwhich, upon calcination will result in the oxide. As with the otherelements, water soluble salts are preferred for the ease with which theymay be uniformly dispersed within the catalyst. Most preferred is ferricnitrate.

Source compounds for the remaining elements may be derived from anysuitable source. For example, cobalt, nickel and magnesium may beintroduced into the catalyst using nitrate salts. Additionally,magnesium may be introduced into the catalyst as an insoluble carbonateor hydroxide which upon heat treating results in an oxide. Phosphorusmay be introduced in the catalyst as an alkaline metal salt or alkalineearth metal salt or the ammonium salt but is preferably introduced asphosphoric acid.

Source compounds for the alkali components of the catalyst may beintroduced into the catalyst as an oxide or as a salt which uponcalcination will yield the oxide.

Solvents, in addition to water, may be used to prepare the mixed metaloxides according to the invention include, but are not limited to,alcohols such as methanol, ethanol, propanol, diols (e.g. ethyleneglycol, propylene glycol, etc.), organic acids such as acetic acid, aswell as other polar solvents known in the art. The metal sourcecompounds are at least partially soluble in the solvent.

As previously noted, the catalyst of the present invention may be usedeither supported or unsupported (i.e. the catalyst may comprise asupport). Suitable supports are silica, alumina, zirconia, titania, ormixtures thereof. The support may be added anytime prior to the catalystprecursor slurry being dried. The support may be added at any timeduring or after the preparation of any mixture of elements, theprecipitate slurry or the catalyst precursor slurry. Further the supportneed not be added in a single point or step (i.e. the support may beadded at multiple points in the preparation. In one embodiment, thesupport is combined with the other ingredients during the preparation ofthe aqueous catalyst precursor slurry. In one embodiment, the support isadded to the precipitate slurry (i.e. after the precipitate slurry isprepared). In one embodiment, the support is combined with the sourcecompound of molybdenum prior to combining the source compound ofmolybdenum with source compounds of the remaining elements in thecatalyst to form the “second mixture” referred to above.

The catalyst precursor slurry is dried and denitrified (i.e. the removalof nitrates) to yield the catalyst precursor. In one embodiment, thecatalyst precursor slurry is dried to form catalyst particles. In oneembodiment, the catalyst precursor slurry is spray-dried intomicrospheroidal catalyst particles. In one embodiment the spray dryeroutlet temperature of between 110° C. and 350° C. dryer outlettemperature, preferably between 110° C. and 250° C., most preferablybetween 110° C. and 180° C. In one embodiment the spray dryer is aco-current flow spray dryer (i.e. the particles are sprayed co-currentto the gas flow). In another embodiment the spray dryer iscountercurrent flow (i.e. the particles are sprayed countercurrent tothe gas flow). In another embodiment the spray dryer is a pressurenozzle type spray dryer. In such spray-drying processes,water-containing solid phase particles are sprayed into contact with hotgas (usually air) so as to vaporize the water. The drying is controlledby the temperature of the gas and the distance the particles travel incontact with the gas. It is generally undesirable to adjust theseparameters to achieve too rapid drying as this results in a tendency toform dried skins on the partially dried particles of the solid phasewhich are subsequently ruptured as water occluded within the particlesvaporizes and attempts to escape. By the same token, it is desirable toprovide the catalyst in a form having as little occluded water aspossible. Therefore, where a fluidized bed reactor is to be used andmicrospheroidal particles are desired, it is advisable to choose theconditions of spray-drying with a view to achieving complete dryingwithout particle rupture. The dried catalyst material is then heated toremove any remaining nitrates. The denitrification temperature may rangefrom 100° C. to 500° C., preferably 250° C. to 450° C.

Finally, the dried and denitrified catalyst precursor is calcined toform the finished catalyst. In one embodiment, the calcination iseffected in air. In another embodiment, the calcination is effected inan inert atmosphere. In one embodiment, the catalyst precursor iscalcined in nitrogen. Calcination conditions include temperaturesranging from about 300° C. to about 700° C., more preferably from about350° C. to about 650° C., and in some embodiments, the calcination maybe at about 600° C. In one embodiment, calcination may be completed inmultiple stages of increasing temperatures. In one embodiment, a firstcalcination step is conducted at a temperature in the range of about300° C. to about 450° C., followed by a second calcination stepconducted at a temperature in the range of about 500° C. to about 650°C.

Ammoxidation Process

The catalysts of the instant invention are useful in ammoxidationprocesses for the conversion of an olefin selected from the groupconsisting of propylene, isobutylene or mixtures thereof, toacrylonitrile, methacrylonitrile and mixtures thereof, respectively, byreacting in the vapor phase at an elevated temperature and pressure saidolefin with a molecular oxygen containing gas and ammonia in thepresence of the catalyst. The catalysts of the instant invention arealso useful for the ammoxidation of methanol to hydrogen cyanide and theammoxidation of ethanol to acetonitrile. In one embodiment employing thecatalysts described herein, methanol and/or ethanol can be co-fed to aprocess for the ammoxidation of propylene, isobutylene or mixturesthereof to acrylonitrile, methacrylonitrile or mixtures thereof, inorder to increase the production of hydrogen cyanide and/or acetonitrileco-products resulting from such process.

Preferably, the ammoxidation reaction is performed in a fluid bedreactor although other types of reactors such as transport line reactorsare envisioned. Fluid bed reactors, for the manufacture of acrylonitrileare well known in the prior art. For example, the reactor design setforth in U.S. Pat. No. 3,230,246, herein incorporated by reference, issuitable.

Conditions for the ammoxidation reaction to occur are also well known inthe prior art as evidenced by U.S. Pat. Nos. 5,093,299; 4,863,891;4,767,878 and 4,503,001; herein incorporated by reference. Typically,the ammoxidation process is performed by contacting propylene orisobutylene in the presence of ammonia and oxygen with a fluid bedcatalyst at an elevated temperature to produce the acrylonitrile ormethacrylonitrile. Any source of oxygen may be employed. For economicreasons, however, it is preferred to use air. The typical molar ratio ofthe oxygen to olefin in the feed should range from 0.5:1 to 4:1,preferably from 1:1 to 3:1.

The molar ratio of ammonia to olefin in the feed in the reaction mayvary from between 0.5:1 to 2:1. There is really no upper limit for theammonia-olefin ratio, but there is generally no reason to exceed a ratioof 2:1 for economic reasons. Suitable feed ratios for use with thecatalyst of the instant invention for the production of acrylonitrilefrom propylene are an ammonia to propylene ratio in the range of 0.9:1to 1.3:1, and air to propylene ratio of 8.0:1 to 12.0:1. The catalyst ofthe instant invention is able to provide high yields of acrylonitrile atrelatively low ammonia to propylene feed ratios of about 1:1 to about1.05:1. These “low ammonia conditions” help to reduce unreacted ammoniain the reactor effluent, a condition known as “ammonia breakthrough”,which subsequently helps to reduce process wastes. Specifically,unreacted ammonia must be removed from the reactor effluent prior to therecovery of the acrylonitrile. Unreacted ammonia is typically removed bycontacting the reactor effluent with sulfuric acid to yield ammoniumsulfate or by contacting the reactor effluent with acrylic acid to yieldammonium acrylate, which in both cases results in a process waste streamto be treated and/or disposed.

The reaction is carried out at a temperature of between the ranges ofabout 260° to 600° C., preferred ranges being 310° to 500° C.,especially preferred being 350° to 480° C. The contact time, althoughnot critical, is generally in the range of 0.1 to 50 seconds, withpreference being to a contact time of 1 to 15 seconds.

The products of reaction may be recovered and purified by any of themethods known to those skilled in the art. One such method involvesscrubbing the effluent gases from the reactor with cold water or anappropriate solvent to remove the products of the reaction and thenpurifying the reaction product by distillation.

The primary utility of the catalyst prepared by the process of theinstant invention is for the ammoxidation of propylene to acrylonitrile.Other utilities include the ammoxidation of propane to acrylonitrile,and the ammoxidation of glycerol to acrylonitrile. The catalyst preparedby the process of the instant invention may also be used for theoxidation of propylene to acrolein and/or acrylic acid. Such processesare typically two stage processes, wherein propylene is converted in thepresence of a catalyst to primarily acrolein in the first stage and theacrolein is converted in the presence of a catalyst to primarily acrylicacid in the second stage. The catalyst described herein is suitable foruse in the first stage for the oxidation of propylene to acrolein.

Specific Embodiments

In order to illustrate the instant invention, catalyst prepared inaccordance with the instant invention were evaluated and compared undersimilar reaction conditions to similar catalysts prepared by prior artmethods outside the scope of the instant invention. These examples areprovided for illustrative purposes only. Catalyst compositions, for eachexample, are as shown after the example number. All catalystpreparations were made with 39+/−2 nm silica sol. Examples designatedwith a “C” are comparative examples.

Example C1

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(0.72)Ce_(1.76)Mo_(12.861)O_(51.704)+50wt % SiO₂

Reaction mixture A was prepared by heating 154.9 ml of deionized waterto 65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (140.8 g) to form a clear colorless solution.

Reaction mixture B was prepared by heating 26.4 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (32.1 g),Ni(NO₃)₂.6H₂O (102.6 g), Mg(NO₃)₂.6H₂O (67.8 g), and Cr(NO₃)₃.9H₂O (1.76g).

Reaction mixture C was prepared by heating 65.35 ml of deionized waterto 65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (59.4 g) to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 170.2 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution wasstifling and heating, sequentially adding Bi(NO₃)₃.5H₂O (30.8 g) andRbNO₃ (2.50 g).

Reaction mixture E was prepared by adding with stifling, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example C2

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(0.75)Ce_(1.73)Mo_(12.861)O_(51.689)+50wt % SiO₂

Reaction mixture A was prepared by heating 154.8 ml of deionized waterto 65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (140.7 g) to form a clear colorless solution.

Reaction mixture B was prepared by heating 26.5 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (32.0 g),Ni(NO₃)₂.6H₂O (102.5 g), Mg(NO₃)₂.6H₂O (67.8 g), and Cr(NO₃)₃.9H₂O (1.76g).

Reaction mixture C was prepared by heating 65.3 ml of deionized water to65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (59.4 g) to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 167.1 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution wasstifling and heating, sequentially adding Bi(NO₃)₃.5H₂O (32.0 g) andRbNO₃ (2.49 g).

Reaction mixture E was prepared by adding with stifling, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example 3

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(0.83)Ce_(1.65)Mo_(12.861)O_(51.649)+50wt % SiO₂

Reaction mixture A was prepared by heating 154.5 ml of deionized waterto 65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (140.5 g) to form a clear colorless solution.

Reaction mixture B was prepared by heating 26.8 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (32.0 g),Ni(NO₃)₂.6H₂O (102.3 g), Mg(NO₃)₂.6H₂O (67.7 g), and Cr(NO₃)₃.9H₂O (1.76g).

Reaction mixture C was prepared by heating 65.2 ml of deionized water to65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (59.3 g) to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 159.2 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution wasstifling and heating, sequentially adding Bi(NO₃)₃.5H₂O (35.4 g) andRbNO₃ (2.49 g).

Reaction mixture E was prepared by adding with stifling, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example 4

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(0.98)Ce_(1.5)Mo_(12.861)O_(51.574)+50wt % SiO₂

Reaction mixture A was prepared by heating 154.0 ml of deionized waterto 65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (140.0 g) to form a clear colorless solution.

Reaction mixture B was prepared by heating 27.5 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (31.9 g),Ni(NO₃)₂.6H₂O (102.0 g), Mg(NO₃)₂.6H₂O (67.45 g), and Cr(NO₃)₃.9H₂O(1.75 g).

Reaction mixture C was prepared by heating 65.0 ml of deionized water to65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (59.1 g) to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 144.2 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution wasstifling and heating, sequentially adding Bi(NO₃)₃.5H₂O (41.7 g) andRbNO₃ (2.48 g).

Reaction mixture E was prepared by adding with stifling, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example 5

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(0.98)Ce_(1.50)Mo_(12.861)O_(x)+50wt % SiO₂

Reaction mixture A was prepared by heating 153 ml of deionized water to55° C. and then adding with stifling ammonium heptamolybdate (137.87 g)to form a clear colorless solution.

Reaction mixture B was prepared by heating 30 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (31.62 g),Ni(NO₃)₂.6H₂O (101.17 g), Mg(NO₃)₂.6H₂O (66.88 g), and Cr(NO₃)₃ 9H₂O(1.740 g).

Reaction mixture C was prepared by heating 65 ml of deionized water to55° C. and then adding with stifling ammonium heptamolybdate (58.6 g) toform a clear colorless solution.

Reaction mixture D was prepared by (i) heating 93.45 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution wasstifling and heating, sequentially adding Bi(NO₃)₃.5H₂O (63.27 g) andRbNO₃ (2.461 g).

Reaction mixture E was prepared by adding with stirring, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example 6

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(1.1)Ce_(1.38)Mo_(12.861)O_(51.514)+50%SiO₂

Reaction mixture A was prepared by heating 153.6 ml of deionized waterto 65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (139.7 g) to form a clear colorless solution.

Reaction mixture B was prepared by heating 28.0 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (31.8 g),Ni(NO₃)₂.6H₂O (101.7 g), Mg(NO₃)₂.6H₂O (67.3 g), and Cr(NO₃)₃.9H₂O (1.75g).

Reaction mixture C was prepared by heating 64.8 ml of deionized water to65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (58.9 g) to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 132.3 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution wasstifling and heating, sequentially adding Bi(NO₃)₃.5H₂O (46.7 g) andRbNO₃ (2.48 g).

Reaction mixture E was prepared by adding with stifling, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example 7

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(1.24)Ce_(1.24)Mo_(12.861)O_(51.444)+50%SiO₂

Reaction mixture A was prepared by heating 1379 ml of deionized water to65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (1253 g) to form a clear colorless solution.

Reaction mixture B was prepared by heating 257 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (285.4 g),Ni(NO₃)₂.6H₂O (912.9 g), Mg(NO₃)₂.6H₂O (603.7 g), and Cr(NO₃)₃.9H₂O(15.7 g).

Reaction mixture C was prepared by heating 582 ml of deionized water to65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (529 g) to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 1067 g of 50 wt % aqueous(NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution was stiflingand heating, sequentially adding Bi(NO₃)₃.5H₂O (472 g) and RbNO₃ (22.2g).

Reaction mixture E was prepared by adding with stirring, silica sol(5488 g, 41 wt % silica) to Reaction mixture A, followed by the additionof Reaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example 8

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(1.3)Ce_(1.18)Mo_(12.861)O_(51.414)+50wt % SiO₂Reaction mixture A was prepared by heating 153.0 ml ofdeionized water to 65° C. and then adding with stirring over 30 minutesammonium heptamolybdate (139.1 g) to form a clear colorless solution.

Reaction mixture B was prepared by heating 28.8 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (31.7 g),Ni(NO₃)₂.6H₂O (101.3 g), Mg(NO₃)₂.6H₂O (67.0 g), and Cr(NO₃)₃.9H₂O (1.74g).

Reaction mixture C was prepared by heating 64.5 ml of deionized water to65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (58.7 g) to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 112.7 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution wasstifling and heating, sequentially adding Bi(NO₃)₃.5H₂O (54.9 g) andRbNO₃ (2.47 g).

Reaction mixture E was prepared by adding with stifling, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example 9

Ni₄Mg₃Fe_(0.9)Rb_(0.162)Cr_(0.05)Bi_(1.35)Ce_(1.13)Mo_(12.861)O_(51.389)+50wt % SiO₂Reaction mixture A was prepared by heating 152.8 ml ofdeionized water to 65° C. and then adding with stirring over 30 minutesammonium heptamolybdate (138.9 g) to form a clear colorless solution.

Reaction mixture B was prepared by heating 29.0 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (31.6 g),Ni(NO₃)₂.6H₂O (101.2 g), Mg(NO₃)₂.6H₂O (66.9 g), and Cr(NO₃)₃.9H₂O (1.74g).

Reaction mixture C was prepared by heating 64.5 ml of deionized water to65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (58.6 g) to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 107.8 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution wasstifling and heating, sequentially adding Bi(NO₃)₃.5H₂O (57.0 g) andRbNO₃ (2.46 g).

Reaction mixture E was prepared by adding with stifling, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example 10

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(1.40)Ce_(1.08)Mo_(12.861)O_(51.364)+50wt % SiO₂Reaction mixture A was prepared by heating 155 ml of deionizedwater to 55° C. and then adding with stifling ammonium heptamolybdate(139.21 g) to form a clear colorless solution.

Reaction mixture B was prepared by heating 31 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (31.69 g),Ni(NO₃)₂.6H₂O (101.40 g), Mg(NO₃)₂.6H₂O (67.04 g), and Cr(NO₃)₃.9H₂O(1.744 g).

Reaction mixture C was prepared by heating 72 ml of deionized water to55° C. and then adding with stifling ammonium heptamolybdate (58.73 g)to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 103.22 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution wasstifling and heating, sequentially adding Bi(NO₃)₃.5H₂O (59.19 g) andRbNO₃ (2.467 g).

Reaction mixture E was prepared by adding with stirring, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example 11

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(1.45)Ce_(1.03)Mo_(12.861)O_(51.339)+50wt % SiO₂Reaction mixture A was prepared by heating 152.5 ml ofdeionized water to 65° C. and then adding with stirring over 30 minutesammonium heptamolybdate (138.6 g) to form a clear colorless solution.

Reaction mixture B was prepared by heating 29.4 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (31.6 g),Ni(NO₃)₂.6H₂O (101.0 g), Mg(NO₃)₂.6H₂O (66.8 g), and Cr(NO₃)₃.9H₂O (1.74g).

Reaction mixture C was prepared by heating 64.3 ml of deionized water to65° C. and then adding with stifling over 30 minutes ammoniumheptamolybdate (58.5 g) to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 98.0 g of 50 wt % aqueous(NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution was stiflingand heating, sequentially adding Bi(NO₃)₃.5H₂O (61.1 g) and RbNO₃ (2.46g).

Reaction mixture E was prepared by adding with stifling, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example C12

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(1.50)Ce_(0.98)Mo_(12.861)Ox+50 wt %SiO₂

Reaction mixture A was prepared by heating 153 ml of deionized water to55° C. and then adding with stifling ammonium heptamolybdate (137.87 g)to form a clear colorless solution.

Reaction mixture B was prepared by heating 30 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (31.62 g),Ni(NO₃)₂.6H₂O (101.17 g), Mg(NO₃)₂.6H₂O (66.88 g), and Cr(NO₃)₃.9H₂O(1.740 g).

Reaction mixture C was prepared by heating 65 ml of deionized water to55° C. and then adding with stifling ammonium heptamolybdate (58.6 g) toform a clear colorless solution.

Reaction mixture D was prepared by (i) heating 93.45 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution wasstifling and heating, sequentially adding Bi(NO₃)₃.5H₂O (63.27 g) andRbNO₃ (2.461 g).

Reaction mixture E was prepared by adding with stirring, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example C13

Ni₄Mg₃Fe_(0.9)Rb_(0.192)Cr_(0.05)Bi_(1.760)Ce_(0.72)Mo_(12.861)Ox+50 wt% SiO₂

Reaction mixture A was prepared by heating 152 ml of deionized water to55° C. and then adding with stifling ammonium heptamolybdate (138.0 g)to form a clear colorless solution.

Reaction mixture B was prepared by heating 31 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (31.43 g),Ni(NO₃)₂.6H₂O (100.53 g), Mg(NO₃)₂.6H₂O (66.48 g), and Cr(NO₃)₃.9H₂O(1.730 g).

Reaction mixture C was prepared by heating 64.5 ml of deionized water to55° C. and then adding with stifling ammonium heptamolybdate (58.23 g)to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 68.23 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution to 55° C., (ii) while the solution wasstifling and heating, sequentially adding Bi(NO₃)₃.5H₂O (73.79 g) andRbNO₃ (2.448 g).

Reaction mixture E was prepared by adding with stirring, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of an orange solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example C14

Ni₄Mg₃Fe_(0.9)Rb_(0.162)Cr_(0.05)Bi_(2.12)Ce_(0.36)Mo_(12.861)O_(50.37)+50wt % SiO₂

Reaction mixture A was prepared by heating 151 ml of deionized water to55° C. and then adding with stifling ammonium heptamolybdate (136.85 g)to form a clear colorless solution.

Reaction mixture B was prepared by heating 32.5 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (31.15 g),Ni(NO₃)₂.6H₂O (99.67 g), Mg(NO₃)₂.6H₂O (65.91 g), and Cr(NO₃)₃.9H₂O(1.714 g).

Reaction mixture C was prepared by heating 70 ml of deionized water to55° C. and then adding with stifling ammonium heptamolybdate (57.74 g)to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 33.82 g of 50 wt %aqueous (NH₄)₂Ce(NO₃)₆ solution plus 10 ml deionized water to 55° C.,(ii) while the solution was stifling and heating, sequentially addingBi(NO₃)₃.5H₂O (88.13 g) and RbNO₃ (2.427 g).

Reaction mixture E was prepared by adding with stirring, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of a solid (this resultingmixture was the precipitate slurry). The stifling of the precipitateslurry was continued for 15 minutes while the temperature was maintainedin the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Example C15

Ni₄Mg₃Fe_(0.9)Rb_(0.162)Cr_(0.05)Bi_(2.48)Ce_(0.00)Mo_(12.861)O_(x)+50wt % SiO₂

Reaction mixture A was prepared by heating 150 ml of deionized water to55° C. and then adding with stifling ammonium heptamolybdate (135.7 g)to form a clear colorless solution.

Reaction mixture B was prepared by heating 33.5 ml of deionized water to55° C. and then adding with stifling Fe(NO₃)₃.9H₂O (30.89 g),Ni(NO₃)₂.6H₂O (98.83 g), Mg(NO₃)₂.6H₂O (65.36 g), and Cr(NO₃)₃.9H₂O(1.699 g).

Reaction mixture C was prepared by heating 63 ml of deionized water to55° C. and then adding with stifling ammonium heptamolybdate (57.25 g)to form a clear colorless solution.

Reaction mixture D was prepared by (i) heating 100 g of 1:10 nitric acidsolution to 55° C., (ii) while the solution was stirring and heating,sequentially adding Bi(NO₃)₃.5H₂O (102.20 g) and RbNO₃ (2.406 g).

Reaction mixture E was prepared by adding with stifling, silica sol (610g, 41 wt % silica) to Reaction mixture A, followed by the addition ofReaction mixture B.

Reaction mixture F was prepared by adding reaction mixture C to reactionmixture D, which resulted in precipitation of a white solid (thisresulting mixture was the precipitate slurry). The stirring of theprecipitate slurry was continued for 15 minutes while the temperaturewas maintained in the 50-55° C. range.

Reaction mixture E was then added to reaction mixture F to form thefinal catalyst precursor slurry.

The catalyst precursor slurry was allowed to stir for one hour while itcooled to approximately 40° C. It was then homogenized in a blender for3 minutes at 5000 rpm. The slurry was then spray dried in a spray dryerat an inlet/outlet temperature of 325/140° C. The resulting powder wasdenitrified by heat treating for 3 hours in air at 290° C., followed byan additional 3 hours at 425° C. The powder was then calcined in air for3 hours at 560° C.

Catalyst Testing

All catalyst were tested in a bench scale reactor for the ammoxidationof propylene to acrylonitrile. All testing was conducted in a 40 ccfluid bed reactor. Propylene was feed into the reactor at the ratesshown in Table 1, between 0.06 and 0.09 WWH (i.e. weight ofpropylene/weight of catalyst/hour). Pressure inside the reactor wasmaintained at 10 psig. Reaction temperature was 430° C. Samples ofreaction products were collected after several days of testing (betweenabout 140 to about 190 hours on stream). Reactor effluent was collectedin bubble-type scrubbers containing cold HCl solution. Off-gas rate wasmeasured with soap film meter, and the off-gas composition wasdetermined at the end of the run with the aid of gas chromatographfitted with a split column gas analyzer. At the end of the recovery run,the entire scrubber liquid was diluted to approximately 200 grams withdistilled water. A weighted amount of 2-butanone was used as internalstandard in a ˜50 gram aliquot of the dilute solution. A 2 μl sample wasanalyzed in a GC fitted with a flame ionization detector and a Carbowax™column. The amount of NH₃ was determined by titrating the free HClexcess with NaOH solution.

TABLE 1 % % % Ex. C₃ = AN AN (a + h)/ No. Catalyst WWH Conv Yield Sela/h d h/b C1 Ni4Mg3Fe0.9Rb0.192Cr0.05Bi0.72Ce1.76Mo12.861 0.06 98.5 81.983.2 0.41 0.354 1.96 O 51.704 + 50 wt % C2Ni4Mg3Fe0.9Rb0.192Cr0.05Bi0.75Ce1.73Mo12.861 0.06 97.8 81.3 83.2 0.430.35 1.92 O 51.689 + 50 wt % 3Ni4Mg3Fe0.9Rb0.192Cr0.05Bi0.83Ce1.65Mo12.861 0.06 98.5 84.0 85.2 0.500.354 1.83 O 51.649 + 50 wt % 4Ni4Mg3Fe0.9Rb0.192Cr0.05Bi0.98Ce1.5Mo12.861 0.06 97.2 82.3 84.6 0.650.35 1.67 O 51.574 + 50 wt % 5Ni4Mg3Fe0.9Rb0.192Cr0.05Bi0.98Ce1.50Mo12.861 0.06 97.8 82.6 84.4 0.650.354 1.67 Ox + 50 wt % 6 Ni4Mg3Fe0.9Rb0.192Cr0.05Bi1.10Ce1.38Mo12.8610.06 97.1 82.8 85.3 0.80 0.35 1.53 O 51.414 + 50 wt % 7Ni4Mg3Fe0.9Rb0.192Cr0.05Bi1.24Ce1.24Mo12.861 0.06 98.6 85 86.2 1.000.354 1.38 Ox + 50 wt % 8 Ni4Mg3Fe0.9Rb0.192Cr0.05Bi1.3Ce1.18Mo12.8610.06 96.3 83.7 88.6 1.10 0.35 1.31 O 51.414 + 50 wt % 9Ni4Mg3Fe0.9Rb0.192Cr0.05Bi1.35Ce1.13Mo12.861 0.06 97.2 82.4 84.8 1.190.354 1.26 O 51.389 + 50 wt % 10Ni4Mg3Fe0.9Rb0.192Cr0.05Bi1.40Ce1.08Mo12.861 0.06 96.4 82.7 85.8 1.300.35 1.2 O 51.364 + 50 wt % 11Ni4Mg3Fe0.9Rb0.192Cr0.05Bi1.45Ce1.03Mo12.861 0.06 95.9 82.4 85.9 1.410.354 1.14 O 51.339 + 50 wt % C12Ni4Mg3Fe0.9Rb0.192Cr0.05Bi1.50Ce0.98Mo12.861 0.06 92.4 73.2 79.2 1.530.35 1.09 Ox + 50 wt % C13 Ni4Mg3Fe0.9Rb0.192Cr0.05Bi1.760Ce0.72Mo12.8610.06 94.7 81.6 86.2 2.44 0.354 0.80 Ox + 50 wt % C14Ni4Mg3Fe0.9Rb0.192Cr0.05Bi2.12Ce0.36Mo12.861 0.06 90.2 70.7 78.4 5.890.35 0.40 O50.37 + 50 wt % C15Ni4Mg3Fe0.9Rb0.192Cr0.05Bi2.48Ce0.00Mo12.861 0.06 93.4 75.9 81.2 ∞ 0.3540.00 Ox + 50 wt % Notes for Table 1 (where applicable): 1. “WWH” isweight of propylene per weight of catalyst per hour in the feed. 2. “%C₃= Conv” is mole percent per pass conversion of propylene to allproducts. 3. “% AN Yield” is percent acrylonitrile yield. 4. “% AN Sel”is percent acrylonitrile selectivity. 5. “a/h” is ratio of bismuth tocerium. 6. “(a + h)/d” is ratio of (atoms of bismuth plus atoms ofcerium) to moles of D. 7. “h/b” is and atomic ratio of cerium to iron.

The data in Table 1 clearly shows the benefit of the present invention.Examples 3-11 with bismuth to cerium ratios (i.e. a/h ratios) within thescope of the claimed invention (i.e. 0.45≦a/h<1.5) exhibit greateracrylonitrile yield and greater acrylonitrile selectivity than thosecatalysts of C1, C2 and C12-C15 which are outside the claimed bismuth tocerium ratio range.

While the foregoing description and the above embodiments are typicalfor the practice of the instant invention, it is evident that manyalternatives, modifications, and variations will be apparent to thoseskilled in the art in light of this description. Accordingly, it isintended that all such alternatives, modifications and variations areembraced by and fall within the spirit and broad scope of the appendedclaims.

1-13. (canceled)
 14. A process for the conversion of an olefin selectedfrom the group consisting of propylene, isobutylene or mixtures thereof,to acrylonitrile, methacrylonitrile, and mixtures thereof, respectively,by reacting in the vapor phase at an elevated temperature and pressuresaid olefin with a molecular oxygen containing gas and ammonia in thepresence of a catalyst wherein the relative ratios of the listedelements in said catalyst are represented by the following formula:Mo_(m)Bi_(a)Fe_(b)A_(c)D_(d)E_(e)F_(f)G_(g)Ce_(h)O_(x) wherein A is atleast one element selected from the group consisting of sodium,potassium, rubidium and cesium; and D is at least one element selectedfrom the group consisting of nickel, cobalt, manganese, zinc, magnesium,calcium, strontium, cadmium and barium; E is at least one elementselected from the group consisting of chromium, tungsten, boron,aluminum, gallium, indium, phosphorus, arsenic, antimony, vanadium andtellurium; F is at least one element selected from the group consistingof lanthanum, praseodymium, neodymium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium thulium, ytterbium, lutetium,scandium, yttrium, titanium, zirconium, hafnium, niobium, tantalum,aluminum, gallium, indium, thallium, silicon, germanium and less thanabout 10 ppm lead; G is at least one element selected from the groupconsisting of silver, gold, ruthenium, rhodium, palladium, osmium,iridium, platinum and mercury; and a, b, c, d, e, f, g, h and x are,respectively, the atomic ratios of bismuth (Bi), iron (Fe), A, D, E, F,G, cerium (Ce) and oxygen (O), relative to “m” atoms of molybdenum (Mo),wherein a is from 0.05 to 7, b is from 0.1 to 7, c is from 0.01 to 5, dis from 0.1 to 12, e is from 0 to 5, f is from 0 to 5, g is from 0 to0.2, h is from 0.01 to 5, m is from 10 to 15, and x is the number ofoxygen atoms required to satisfy the valence requirements of the othercomponent elements present; wherein 0.5≦a/h<1.5 and 0.3≦(a+h)/d≦1 and0.8≦a/h≦5.
 15. A process for the conversion of an olefin selected fromthe group consisting of propylene, isobutylene or mixtures thereof, toacrolein/acrylic acid, methacrolein/methacrylic acid, and mixturesthereof, respectively, by reacting in the vapor phase at an elevatedtemperature and pressure said olefin with a molecular oxygen containinggas in the presence of a catalyst wherein the relative ratios of thelisted elements in said catalyst are represented by the followingformula:Mo_(m)Bi_(a)Fe_(b)A_(c)D_(d)E_(e)F_(f)G_(g)Ce_(h)O_(x) wherein A is atleast one element selected from the group consisting of sodium,potassium, rubidium and cesium; and D is at least one element selectedfrom the group consisting of nickel, cobalt, manganese, zinc, magnesium,calcium, strontium, cadmium and barium; E is at least one elementselected from the group consisting of chromium, tungsten, boron,aluminum, gallium, indium, phosphorus, arsenic, antimony, vanadium andtellurium; F is at least one element selected from the group consistingof lanthanum, praseodymium, neodymium, samarium, europium, gadolinium,terbium, dysprosium, holmium, erbium thulium, ytterbium, lutetium,scandium, yttrium, titanium, zirconium, hafnium, niobium, tantalum,aluminum, gallium, indium, thallium, silicon, germanium and less thanabout 10 ppm lead; G is at least one element selected from the groupconsisting of silver, gold, ruthenium, rhodium, palladium, osmium,iridium, platinum and mercury; and a, b, c, d, e, f, g, h and x are,respectively, the atomic ratios of bismuth (Bi), iron (Fe), A, D, E, F,G, cerium (Ce) and oxygen (O), relative to “m” atoms of molybdenum (Mo),wherein a is from 0.05 to 7, b is from 0.1 to 7, c is from 0.01 to 5, dis from 0.1 to 12, e is from 0 to 5, f is from 0 to 5, g is from 0 to0.2, h is from 0.01 to 5, m is from 10 to 15, and x is the number ofoxygen atoms required to satisfy the valence requirements of the othercomponent elements present; wherein 0.5≦a/h≦1.5 and 0.3≦(a+h)/d≦1 and0.8≦a/h≦5. 16-17. (canceled)
 18. The catalytic composition of claim 14,wherein 0.65≦a/h<1.5.
 19. The catalytic composition of claim 14, wherein0.7≦a/h<1.5.
 20. The catalytic composition of claim 14, wherein0.8≦a/h<1.5.
 21. The catalytic composition of claim 14, wherein0.90≦a/h<1.5.
 22. The catalytic composition of claim 14, wherein0.90≦a/h≦1.2.
 23. The catalytic composition of claim 15, wherein0.65≦a/h<1.5.
 24. The catalytic composition of claim 15, wherein0.7≦a/h<1.5.
 25. The catalytic composition of claim 15, wherein0.8≦a/h<1.5.
 26. The catalytic composition of claim 15, wherein0.90≦a/h<1.5.
 27. The catalytic composition of claim 15, wherein0.90≦a/h≦1.2.